问题:

I am trying to practice myself in writing some SPARQL queries. Does anybody know where I can find the best material? Where I can find some RDF file and some tasks to try to write my own SPARQL queries. I am good with SQL, and I just need some material to learn to write in SPARQL.

回答1:

All sample RDF and queries from the O'Reilly book "Learning SPARQL" are available on the book's home page at learningsparql.com. (Full disclosure: I wrote it.)

回答2:

data.gov and DataHub have a lot of downloadable RDF data sets. If a public SPARQL endpoint is available, DataHub usually lists it. For example: the Rijksmuseum page offers RDF downloads and a link to the endpoint.

My Experiment has a tutorial with examples and a working endpoint.

If you download Jena, you get their example RDF files and SPARQL queries.

Uniprot has a SPARQL endpoint with examples. The RDF is available for download. some of the files are quite large.

There's a large number of downloadable ontologies in RDF format at the OBO Foundry.

Watch this: Probe the Semantic Web with SPARQL

SPARQL Cheat Sheet Slide Deck

As mentioned above: the website for Bob DuCharme's excellent Learning SPARQL Book